This invention relates to a pneumatic plug device for sealing pipelines. Particularly, this invention deals with multi-size expansible penumatic plug devices used for sealing the interior of a range of pipeline diameters.
For example, the multi-size pneumatic plug devices according to the invention are constructed for sealing the interior of pipeline diameters which range in dimension from 12-18, 16-24 or 24-36 inches. Thus, the multi-size expansible pneumatic plug devices according to the invention are designed for sealing a range of pipeline sections rather than being designed to seal a specific or single pipeline diameter.
The expansible pneumatic plug devices are constructed of elements that permit easy manufacturing assembly and which result in multi-size pneumatic plug devices that are durable, versatile and effective in sealing pipeline sections.
In the past, several types of expansible pneumatic plug devices have been proposed or utilized for use in sealing varying diameter pipeline sections. However, these plug devices have generally been complex in construction, limited in use, unsuited for multi-size use, difficult to assemble and expensive to manufacture.
For example, some prior art devices are inflatable packer devices having elastomeric sleeve members that are retained to the device body by exteriorly disposed clamping bands. This attachment means is generally unsuited for securely holding sleeve members during repeated use of multi-size pneumatic devices. Additionally, sleeve members have been proposed having surface patterns which are designed primarily for gripping interior pipeline surfaces as opposed to sealing these surfaces.
Other prior art devices have also proposed complex means to retain their respective sleeve members to the structural supporting elements of their respective devices, such as by using threaded end members, and they have also proposed devices having only one supported end member. Still other devices have been proposed for specific applications which are not suitable for the inflation pressures needed in sealing applications for which the multi-size pneumatic plug devices of this invention are designed.
Further, prior art devices have been proposed which utilize sleeve member configurations which result in low air volume leakage at low sealing or pipeline back pressures.
The multi-size expansible pneumatic plug devices of this invention are provided to overcome the problems and limitations associated with these prior art devices.